Our hoe is leaking badly between the boom spool section and the stabilizer spool section of the boom control valve assembly. From what I gather, I will need to replace the o-rings in between all of the sections once I disassemble this thing. Feel free to comment. My primary question deals with the boom spool. When the hoe was operational (but leaking badly) I could feel a hang up in the spool when the boom control lever was pulled. I can only assume that a piece of the oring from in between the sections has moved into the boom spool section. I figure I should replace seals on spool in this section. Do I need to replace parts on the relief side of the valve also? And do I need to replace the shims in between each section? What esle should I be replacing while I have this vavle assembly out of the machine? Thanks for any info you might be able to contribute!
Welcome to HEF @Kansan Whatever the problem with the spool binding, it won't matter, because chances are you will have a small crack in the boom lift section. A new section will be required to repair the leak..... The orings between the sections are rarely at fault, you should replace them all during assembly, you can reuse the shims if you want, but they are chicken feed. I have replaced more than a few of these sections over the years, so a crack detection test while it is apart is mandatory. Here's what to look for -
Thanks alrman! I will tear the assembly apart today and check for a crack. If it was your tractor would you replace all the seals in the assembly while you had it out or just fix whats broke and slam it back together? Im leaning towards the "slam it back together" option for money reasons.
So after getting it apart, I did notice that the lowest o-ring between the sections was misshapen/pulled away from the rim of the recess where it was placed. In that same spot the o-ring was scuffed up like the leaking hydraulic fluid had cut it alittle bit. Still doesn't exsplain the hang up I was feeling in that spool while it was in operation. The spool looks good and functions smoothly now. Comments? btw: I tried to post pic's, doesn't look like they're going to show up.
Also wondering if anyone knows what the studs should be torqued to after reassembled.
Have you done a crack detection test on the section? If it's cracked it will continue to leak...... I always replace all the orings between the sections. Torque the nuts to 25 ft lbs.
No crack test yet. I called the Case dealer to ask if they could do it. They said no and referred me to a hydraulic repair shop. Is ther a way to do the test myself without spending a bunch of money?
Google 'dye penetrant inspection kit' - should be 3 x aerosol cans - cleaner, red dye, developer If you can buy the individual cans (in this situation) you will only really need to buy 'the developer' - which is the last step of the test. 1) Clean the surface to be tested with supplied the cleaner or brake cleaner 2) allow to dry 3) spray the red dye & allow time (read instructions on can) to penentrate any flaws (this step can be skipped due to oil content inside the crack) 4) clean off the dye (if used) with the cleaner & allow to dry 5) spray the white developer & allow to dry - it will pull the dye/oil from inside the crack for you to see.
The binding may have been caused by uneven torque or bolt loosening, this may have caused your O-ring to be misplaced. If you know a good machine shop see if they will do a magnaflux on the section or they do make a crack detection spray that you can get.
Sweet! That sounds simple enough. Thanks alrman!! You have been very helpful.
If the shims are not between the valve sections the spools will bind and it will leak between the sections.
Yes that's correct. I should have clarified, that the shims need to be fitted, whether new or reused.
I received my o-rings, shims, and dye penetrant today. After using the penetrant to perform the crack test, the vavle section that was leaking does indeed have a crack.( you called it alrman. Well done, and thank you for sharing your expertise with me! Now with a broken heart, I will begin the search for a new valve body. If this were your machine, would you consider purchasing a used valve section or just bite the $2700 bullet on a new one?
If you can find a used one that is good it should be ok.
Like @Coy Lancaster says, IF you can find one & it's not cracked ...... Unfortunately, CNH have in recent years, increased dramatically, (doubled) the price on those sections. It seems they don't really care about or want to help their customers who are dealing with CNH factory design faults.